162173 Ryugu

162173 Ryugu
	Color image of Ryugu taken by Hayabusa2, 2018
Discovery
Discovered by	LINEAR
Discovery site	Lincoln Lab's ETS
Discovery date	10 May 1999
Designations
MPC designation	(162173) Ryugu
Pronunciation	/riˈuːɡuː/; Japanese: [ɾjɯːɡɯː]
Named after	Ryūgū; ("Dragon palace")
Alternative designations	1999 JU3
Minor planet category	Apollo · NEO · PHA
Orbital characteristics
	Epoch 12 December 2011 (JD 2455907.5)
	Uncertainty parameter 0
Observation arc	30.32 yr (11,075 d)
Aphelion	1.4159 AU
Perihelion	0.9633 AU
Semi-major axis	1.1896 AU
Eccentricity	0.1902
Orbital period (sidereal)	1.30 yr (474 d)
Mean anomaly	3.9832°
Mean motion	0° 45m 34.56s / day
Inclination	5.8837°
Longitude of ascending node	251.62°
Argument of perihelion	211.43°
Earth MOID	0.0006 AU (0.2337 LD)
Physical characteristics
Dimensions	1004 m × 876 m
Mean radius	448±2 m
Equatorial radius	502±2 m
Polar radius	438±2 m
Volume	0.377±0.005 km3
Mass	(4.50±0.06)×1011 kg
Mean density	1.19±0.03 g cm−3
Equatorial surface gravity	1/80,000 g
Synodic rotation period	7.63262±0.00002 h
Axial tilt	171.64°±0.03°
North pole right ascension	+96.40°±0.03°
North pole declination	−66.40°±0.03°
Geometric albedo	0.037±0.002; 0.042±0.003; 0.047±0.003; 0.063±0.020; 0.07±0.01; 0.078±0.013
Spectral type	SMASS = Cg · C · Cb
Absolute magnitude (H)	18.69±0.07 (R); 18.82; 19.2; 19.25±0.03; 19.3

162173 Ryugu (provisional designation 1999 JU₃) is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately 900 metres (3,000 ft) in diameter and is a dark object of the rare spectral type Cb,^[11] with qualities of both a C-type asteroid and a B-type asteroid. In June 2018, the Japanese spacecraft Hayabusa2 arrived at the asteroid.^[12] After making measurements and taking samples, Hayabusa2 left Ryugu for Earth in November 2019^[13]^[14] and returned the sample capsule to Earth on 5 December 2020.^[14] The samples showed the presence of organic compounds, such as uracil (one of the four components in RNA) and vitamin B3.

^ ^a ^b ^c ^d Cite error: The named reference MPC-object was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference jpldata was invoked but never defined (see the help page).
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Cite error: The named reference Watanabe et al. 2019 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference SpaceFlightNow was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Abe-2008 was invoked but never defined (see the help page).
^ Cite error: The named reference Liang-liang-2014 was invoked but never defined (see the help page).
^ ^a ^b ^c Cite error: The named reference Muller-2017a was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Hasegawa-2008 was invoked but never defined (see the help page).
^ Cite error: The named reference Campins-2009b was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Kim-2013 was invoked but never defined (see the help page).
^ ^a ^b Sugita, S.; Honda, R.; Morota, T.; Kameda, S.; Sawada, H.; Tatsumi, E.; Honda, C.; Yokota, Y.; Yamada, M.; Kouyama, T.; Sakatani, N. (July 2019). "Ryugu's Parent-Body Processes Estimated from Hayabusa2 Multi-Band Optical Observations". LPICo. 82 (2157): 6366. Bibcode:2019LPICo2157.6366S. ISSN 0161-5297.
^ Chang, Kenneth; Stirone, Shannon (19 March 2019). "The Asteroid Was Shooting Rocks Into Space. 'Were We Safe in Orbit?'". The New York Times. Retrieved 21 March 2019. NASA's Osiris-Rex and Japan's Hayabusa2 spacecraft reached the space rocks they are surveying last year, and scientists from both teams announced early findings on Tuesday.
^ Stephen Clark (13 November 2019). "Japanese sample return craft departs asteroid, heads for Earth"./
^ ^a ^b Cite error: The named reference NYT-20201205 was invoked but never defined (see the help page).

[MPC-object-1] Cite error: The named reference MPC-object was invoked but never defined (see the help page).

[jpldata-2] Cite error: The named reference jpldata was invoked but never defined (see the help page).

[Watanabe_et_al._2019-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Cite error: The named reference Watanabe et al. 2019 was invoked but never defined (see the help page).

[SpaceFlightNow-4] Cite error: The named reference SpaceFlightNow was invoked but never defined (see the help page).

[Abe-2008-5] Cite error: The named reference Abe-2008 was invoked but never defined (see the help page).

[Liang-liang-2014-6] Cite error: The named reference Liang-liang-2014 was invoked but never defined (see the help page).

[Muller-2017a-7] Cite error: The named reference Muller-2017a was invoked but never defined (see the help page).

[Hasegawa-2008-8] Cite error: The named reference Hasegawa-2008 was invoked but never defined (see the help page).

[Campins-2009b-9] Cite error: The named reference Campins-2009b was invoked but never defined (see the help page).

[Kim-2013-10] Cite error: The named reference Kim-2013 was invoked but never defined (see the help page).

[:0-11] Sugita, S.; Honda, R.; Morota, T.; Kameda, S.; Sawada, H.; Tatsumi, E.; Honda, C.; Yokota, Y.; Yamada, M.; Kouyama, T.; Sakatani, N. (July 2019). "Ryugu's Parent-Body Processes Estimated from Hayabusa2 Multi-Band Optical Observations". LPICo. 82 (2157): 6366. Bibcode:2019LPICo2157.6366S. ISSN 0161-5297.

[NYT-20190319-12] Chang, Kenneth; Stirone, Shannon (19 March 2019). "The Asteroid Was Shooting Rocks Into Space. 'Were We Safe in Orbit?'". The New York Times. Retrieved 21 March 2019. NASA's Osiris-Rex and Japan's Hayabusa2 spacecraft reached the space rocks they are surveying last year, and scientists from both teams announced early findings on Tuesday.

[spaceflightnow-13] Stephen Clark (13 November 2019). "Japanese sample return craft departs asteroid, heads for Earth"./

[NYT-20201205-14] Cite error: The named reference NYT-20201205 was invoked but never defined (see the help page).

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